Above Sea Level Barometer Reading,Temperature Correction Calculator

This calculator requires the use of Javascript enabled and capable browsers. This script determines the error in an observed barometer reading, based on elevation above (or below) sea level of the barometer and the outside air temperature. ; the higher the elevation, the lower the pressure. With the barometer at elevations above sea level, the correction should be added since it is a negative value; below sea level, the value is also added but the value is positive. The default values are typical for the general lower desert area of Southern California. If you wish to show below sea level changes, just use a negative number for the appropriate elevation. To use the calculator, enter the elevation of the barometer, the air temperature (OAT) and the known and observed barometer reading, in any of the possible designations, then click on Calculate. Actual calculations are done on inches of mercury, feet and degrees F. Results are yielded in both inches of mercury and millibars (mb). The metric unit hPa (hectoPascal) is for all practical purposes, identical to the pressure unit designated as millibars; in reality, there is a very small difference, but the scientific community accepts them as the same. There is also an elevation correction chart, for a given temperature, below the calculator.

The standard value for atmospheric pressure at sea level (ATM) is equal to: